How to Measure Network Speed?

Even if most people use the ‘ping‘ command to test a network connection this tool is not build to get a realistic indication about a network connection. This is due to the internal protocol used by ping. If you really want to know how fast is your network connection – e.g. between to servers – you should use the command line tool ‘iperf‘.

If you want to measure the network performance between to servers – e.g. server-a and server-b, first start the tool on the one side of your two servers:

server-a:$ iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size:  128 KByte (default)
------------------------------------------------------------

This command starts a server listening on port 5001 (you can change the port number if blocked by firewall rules).

Now you can start a test with a client connection from server-b to server-a:

server-b:$ iperf -c server-a
------------------------------------------------------------
Client connecting to server-a, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  3] local 10.0.0.2 port 55622 connected with 10.0.0.3 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.09 GBytes   935 Mbits/sec

in this example, ipref is sending about 1GB from server A to server B with a network speed of 930Mbits per second.